1. Field of the Invention
The present invention relates generally to a piston for an internal combustion engine. Particularly, the invention relates to a piston made of aluminum alloy.
2. Description of The Prior Art
In modern automotive products engines are manufactured which run at high revolution speeds. For this reason cylinder blocks, or cylinder liners of aluminum alloy are widely used for their lightweight characteristics. Aluminum alloy is also a preferred material for pistons, however, an aluminum piston disposed in an an aluminum cylinder block incurs a high degree of abrasion, and/or scuffing of the piston head and skirt due to the rubbing contact of to components of the same material. For this reason, manufacturers seek so increase the abrasion resistance of aluminum pistons by including an anti-abrasion layer of another material such as alumite.
One such piston is exemplified by Japanese Patent Application First Publication 63-289370 in which an alumite layer is provided around a first piston ring groove and/or a piston skirt. However, this procedure does not fully satisfy the anti-abrasion requirements for modern high speed engines, therefore, a further improved abrasion and scuff resistant piston construction has been required.